<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
        "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
    <title>将jQuery对象转换为DOM对象</title>
    <meta charset="utf-8">
    
</head>
<body>
    姓名：<input type="text" id="username" name="username"/>
    <input type="button" id="myBtn" value="提交"/>
</body>
</html>